Method of making dense composites of bulk-solidifying amorphous alloys and articles thereof

ABSTRACT

A method of making composites of bulk-solidifying amorphous alloys, and articles made thereof, containing at least one type or reinforcement material, wherein the composite material preferably comprises a high volume fraction of reinforcement material and is fully-dense with minimum porosity are provided.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a National Stage of International Application No.PCT/US2003/22522 filed on Jul. 17, 2003 which claims the benefit of U.S.Provisional Application No. 60/397,981, filed Jul. 17, 2002.

FIELD OF INVENTION

The present invention relates to a method of making composites ofbulk-solidifying amorphous alloys and articles made thereof; and moreparticularly to a method of producing a bulk-solidifying amorphouscomposite having a high volume fraction of reinforcement materialtherein.

BACKGROUND OF THE INVENTION

Bulk solidifying amorphous alloys are a recently discovered family ofamorphous alloys, which can be cooled at substantially lower coolingrates, of about 500 K/sec or less, and retain their amorphous atomicstructure substantially. As such, they can be produced in thickness of1.0 mm or more, substantially thicker than conventional amorphousalloys, which have typical thicknesses of 0.020 mm and which requirecooling rates of 10⁵ K/sec or more.

Because of their improved properties, bulk-solidifying amorphous alloyshave been found to be a useful matrix material for a variety ofreinforcement material, including composite materials. Such compositematerials and methods of making such composite materials have beendisclosed, for example, U.S. Pat. Nos. 5,567,251; 5,866,254; 5,567,532;and 6,010,580.

However, the processing of such bulk-solidifying amorphous compositeswith high volume fractions of reinforcement material poses somechallenges and hinders the development and use of such composites. Forexample, thus far composite articles made with bulk-solidifyingamorphous materials have typically limited to materials where the volumefraction of particulate reinforcement material is less than 75%. Inaddition, it has proven difficulty to produce a compositebulk-solidifying amorphous material having a high volume fraction offine carbon fiber reinforcement material.

Accordingly, a need exists to produce a fully dense bulk-solidifyingamorphous composite having a high volume fraction of reinforcementmaterial therein.

SUMMARY OF THE INVENTION

The current invention is directed to a method of making composites ofbulk-solidifying amorphous alloys, and articles made thereof, containingat least one type of reinforcement material, wherein the compositematerial preferably comprises a high volume fraction of reinforcementmaterial and is fully-dense with minimum porosity by performing thesteps of the process required to retain the amorphous phase and/or formnear-to-net shape articles only after the composite material has beendensified.

In one embodiment the bulk solidifying amorphous alloys comprisematerials selected from the group described by the molecular equation:(Zr,Ti)_(a)(Ni,Cu,Fe)_(b)(Be,Al,Si,B)_(c), where a is in the range offrom 30 to 75, b is in the range of from 5 to 60, and c in the range offrom 0 to 50 in atomic percentages. Further, the bulk-solidifyingamorphous alloys can contain amounts of other transition metals up to20% atomic, and more preferably metals such as Nb, Cr, V, Co. Apreferable alloy family is (Zr,Ti)_(a)(Ni,Cu)_(b)(Be)_(c), where a is inthe range of from 40 to 75, b is in the range of from 5 to 50, and c inthe range of from 5 to 50 in atomic percentages.

In still another embodiment, embodiment the bulk solidifying amorphousalloys comprise materials selected from the group described by themolecular equation: (Zr,Ti)_(a)(Ni,Cu)_(b)(Be)_(c), where a is in therange of from 45 to 65, b is in the range of from 7.5 to 35, and c inthe range of from 10 to 37.5 in atomic percentages. Another preferablealloy family is (Zr)_(a) (Nb,Ti)_(b) (Ni,Cu)_(c)(Al)_(d), where a is inthe range of from 45 to 65, b is in the range of from 0 to 10, c is inthe range of from 20 to 40 and d in the range of from 7.5 to 15 inatomic percentages.

In yet another embodiment, the bulk-solidifying amorphous alloys areferrous metals (Fe, Ni, Co) based compositions. One exemplarycomposition of such alloys is Fe₇₂Al₅Ga₂P₁₁C₆B₄.

In still yet another embodiment, the bulk-solidifying amorphous alloyscontain a ductile crystalline phase precipitate.

In another embodiment, the reinforcement material is any material whichis stable at greater temperatures than the melting temperatures of thebulk-solidifying amorphous alloy composition. In such an embodiment, thereinforcement material may comprise refractory metals such as tungsten,molybdenum, tantalum, niobium and their alloys; ceramics such as SiC,SiN, BC, TiC, WC, SiO2; and other refractory materials such as diamond,graphite and carbon fiber.

In another embodiment the current invention is directed to a method offorming bulk-solidifying amorphous composite materials comprising adensification step wherein the packing efficiency of the reinforcementmaterial can be improved to provide the desired high density.

In still another embodiment, the feedstock is a blended mixture ofreinforcement material and bulk solidifying amorphous alloy composition.In such an embodiment, the reinforcement material can be in a variety offorms such as wire, fiber, loose particulate, foam or sintered preforms.

In still yet another embodiment the packing density of the feedstockmixture is preferably 30% and higher and most preferably 50% and higher.

In still yet another embodiment, the feedstock mixture is blended andpressed under vacuum.

In still yet another embodiment, the provided feedstock mixture iscanned and sealed under vacuum by a soft and malleable metal. In such anembodiment, the vacuum is preferably better than 10⁻³ Torr.

In still yet another embodiment, the bulk-solidifying amorphous alloyhas a ΔT of larger than 60° C., and preferably larger than 90° C.

In still yet another embodiment, the densification step is carried outthrough an extrusion process above the melting temperature of thebulk-solidifying amorphous alloy composition.

In still yet another embodiment, the densification step is carried outby applying a hydro-static pressure above the melting temperature of thebulk-solidifying amorphous alloy composition.

In still yet another embodiment, the densification step is carried outthrough an hot-isostatic process (HIP) process above the meltingtemperature of the bulk-solidifying amorphous alloy composition.

In still yet another embodiment, the feedstock mixture isfully-densified having a packing efficiency greater than 99% and mostpreferably 100%.

In still yet another embodiment, the method comprises a first coolingstep wherein the densified mixture is cooled sufficiently fast to retainsubstantially all of the amorphous structure of the bulk solidifyingamorphous alloy composition. In such an embodiment, subsequently thedensified mixture is heated and formed/shaped around or above the glasstransition of temperature of bulk-solidifying amorphous alloy.

In still yet another embodiment, the forming/shaping step is carried outabove the melting temperature. In such an embodiment, the re-heating ofthe densified mixture in the forming/shaping cycle may be extended totemperatures with an increased superheat of at least 50° C. above thetemperatures used in the densification step.

In another embodiment, the reinforcement material is tungsten metal orparticulate tungsten metal and comprises a volume fraction of greaterthan 75% of the densified composite material.

In yet another embodiment, the reinforcement material is particulatetungsten metal and comprises a volume fraction of greater than 85% inthe densified composite material.

In still another embodiment, the reinforcement material is SiC,particulate SiC, or SiC fiber and comprises a volume fraction of greaterthan 75% in the densified composite material; or a volume fraction ofgreater than 85% in the densified composite material.

In still yet another embodiment, the reinforcement material is Diamondor synthetic diamond and comprises a volume fraction of greater than 75%in the densified composite material; or a volume fraction of greaterthan 85% in the densified composite material.

In still yet another embodiment, the reinforcement material is carbonfiber and comprises a volume fraction of greater than 50% in thedensified composite material; or a volume fraction of greater than 75%in the densified composite material; or a volume fraction of greaterthan 85% in the densified composite material.

In still yet another embodiment, the composite material comprisesreinforcement material at a volume fraction of greater than 75% in thedensified composite material; or a volume fraction of greater than 85%in the densified composite material.

In another embodiment, the invention is directed to an article made ofthe composite material. In one such embodiment, the article is acylindrical rod with an aspect ratio of greater than 10 (defined aslength divided by diameter) and comprises tungsten metal as thereinforcement material at a volume fraction of greater than 75%. Inanother such embodiment, the article of composite material is acylindrical rod with an aspect ratio of greater than 15.

In yet another embodiment, the article is at least 0.5 mm in alldimensions.

In still another embodiment, the article of composite material is acylindrical rod with an aspect ratio of greater than 10 and with adiameter of at least 10 mm.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features and advantages of the invention will beapparent from the following detailed description, appended claims, andaccompanying drawings, in which:

FIG. 1 is a schematic of an exemplary microstructure of an exemplarycomposite material according to the present invention;

FIG. 2 is a flow chart of a method according to a second exemplaryembodiment of the current invention;

FIG. 3 is a flow chart of a method according to one exemplary embodimentof the current invention; and

FIG. 4 is a flow chart of a method according to a second exemplaryembodiment of the current invention.

DETAILED DESCRIPTION OF THE INVENTION

The current invention is directed to a method of making composites ofbulk-solidifying amorphous alloys, and articles made thereof, containingat least one type of reinforcement material, wherein the compositematerial preferably comprises a high volume fraction of reinforcementmaterial and is fully-dense with minimum porosity. The materialsaccording to this invention are referred to as “bulk-solidifyingamorphous alloy matrix composites” herein.

Generally, there are three main objectives in processing and fabricationof amorphous alloy composites with high volume fraction of reinforcementmaterial:

1) Achieving high packing density of the matrix and the reinforcement tominimize the porosity in the final product.

2) Retaining the amorphous state of the matrix alloy.

3) The ability to form the composite material into near-to-net shapeobjects with very low aspect ratios.

Unfortunately, it is not feasible to achieve all three objectivessimultaneously. Accordingly, in the present process the steps ofretaining the amorphous phase and/or forming near-to-net shape articlesis delayed until after the composite material has been densified.Accordingly, it has been found that bulk solidifying amorphousalloy-matrix composite material having a high volume fraction ofreinforcement material and with minimal porosity can be achieved.

A composite material generally refers to a material that is aheterogeneous mixture of two different material phases. FIG. 1illustrates a microstructure of a bulk-solidifying composite material 10made by the present approach. The composite material 10 is a mixture oftwo phases, a reinforcement phase 12 and a bulk-solidifying amorphousmetal-matrix phase 14 that surrounds and bonds the reinforcement phase12.

Although any mix of reinforcement particles may be utilized, in oneexemplary embodiment a substantially uniform array of reinforcementparticle phase within the metal-matrix phase is attained. Regardless ofthe distribution of particles, it is preferable that the reinforcementphase 12 occupies from about 50 to about 90 volume percent of the totalof the reinforcement phase and the amorphous alloy-matrix phase,although phase percentages outside this range are operable. In a mostpreferred form of this embodiment, the reinforcement phase occupiesgreater than about 75% by volume percent of the total material; and in amost preferred embodiment the reinforcement phase occupies greater thanabout 85% by volume of the total material.

Turning to the bulk-solidifying materials 14 of the composites of thecurrent invention. Bulk solidifying amorphous alloys are recentlydiscovered family of amorphous alloys, which can be cooled atsubstantially lower cooling rates, of about 500 K/sec or less, andretain their amorphous atomic structure substantially. As such, they canbe produced in thickness of 1.0 mm or more, substantially thicker thanconventional amorphous alloys of typically 0.020 mm which requirecooling rates of 10⁵ K/sec or more. U.S. Pat. Nos. 5,288,344; 5,368,659;5,618,359; and 5,735,975 (the disclosure of each of which isincorporated herein by reference in its entirety) disclose such bulksolidifying amorphous alloys. A family of bulk solidifying amorphousalloys can be described as (Zr,Ti)_(a)(Ni,Cu, Fe)_(b)(Be,Al,Si,B)_(c),where a is in the range of from 30 to 75, b is in the range of from 5 to60, and c in the range of from 0 to 50 in atomic percentages.Furthermore, those alloys can accommodate substantial amounts of othertransition metals up to 20% atomic, and more preferably metals such asNb, Cr, V, Co. A preferable alloy family is(Zr,Ti)_(a)(Ni,Cu)_(b)(Be)_(c), where a is in the range of from 40 to75, b is in the range of from 5 to 50, and c in the range of from 5 to50 in atomic percentages. Still, a more preferable composition is(Zr,Ti)_(a)(Ni,Cu)_(b)(Be)_(c), where a is in the range of from 45 to65, b is in the range of from 7.5 to 35, and c in the range of from 10to 37.5 in atomic percentages. Another preferable alloy family is(Zr)_(a) (Nb,Ti)_(b) (Ni,Cu)_(c)(Al)_(d), where a is in the range offrom 45 to 65, b is in the range of from 0 to 10, c is in the range offrom 20 to 40 and d in the range of from 7.5 to 15 in atomicpercentages.

Another set of bulk-solidifying amorphous alloys are ferrous metals (Fe,Ni, Co) based compositions. Examples of such compositions are disclosedin U.S. Pat. No. 6,325,868, (A. Inoue et. al., Appl. Phys. Lett., Volume71, p 464 (1997)), (Shen et. al., Mater. Trans., JIM, Volume 42, p 2136(2001)), and Japanese patent application 2000126277 (Publ. #0.2001303218A), all of which are incorporated herein by reference. One exemplarycomposition of such alloys is Fe₇₂Al₅Ga₂P₁₁C₆B₄. Another exemplarycomposition of such alloys is Fe₇₂Al₇Zr₁₀Mo₅W₂B₁₅. Although, these alloycompositions are not as processable to the degree of Zr-base alloysystems, they can be still be processed in thicknesses around 1.0 mm ormore, sufficient enough to be utilized in the current invention.

Although any of the above bulk-solidifying amorphous alloys may beutilized, in one preferred embodiment the bulk-solidifying amorphousalloy has a ΔT of larger than 60° C. and preferably larger than 90° C.ΔT defines the extent of supercooled liquid regime above the glasstransition temperature, to which the amorphous phase can be heatedwithout significant crystallization in a typical Differential ScanningCalorimetry experiment.

In general, crystalline precipitates in bulk amorphous alloys are highlydetrimental to their properties, especially to the toughness andstrength, and as such generally preferred to a minimum volume fractionpossible. However, there are cases in which, ductile crystalline phasesprecipitate in-situ during the processing of bulk amorphous alloys,which are indeed beneficial to the properties of bulk amorphous alloysespecially to the toughness and ductility. Such bulk amorphous alloyscomprising such beneficial precipitates are also included in the currentinvention. One exemplary case is disclosed in (C. C. Hays et. al,Physical Review Letters, Vol. 84, p 2901, 2000), the disclosure of whichis incorporated herein by reference.

Turning now to the reinforcement material, the reinforcement phase 12 ofthe composite material 10 can be any material which is stable (i.e.,having a melting temperature or sublimation point) at greatertemperatures than the melting temperatures of the bulk-solidifyingamorphous alloy composition. Preferably, the reinforcement materialcomprise refractory metals such as tungsten, molybdenum, tantalum,niobium and their alloys, ceramics such as SiC, SiN, BC, TiC, WC, SiO2or other refractory materials such as diamond, graphite and carbonfiber.

The current invention is also directed to a method of making thecomposites described above. The method comprising the followingsteps: 1) providing a feedstock mixture of reinforcement material andbulk-solidifying amorphous alloy composition; 2) densifying the mixtureby applying pressure above the melting temperature of thebulk-solidifying amorphous alloy composition; 3) cooling the densifiedmixture below the glass transition temperature of the bulk-solidifyingamorphous alloy composition; 4) reheating the densified mixture above aforming temperature; 5) forming into the final a desired shape; and 6)quenching the formed article to ambient temperature. A flow-chart ofthis general method is provided in FIG. 2.

Although any feedstock (step 1) mixture of amorphous material andreinforcement material may be provided, the provided feedstock ispreferably a blended mixture of reinforcement material and a feedstockof bulk solidifying amorphous alloy. In turn the reinforcement materialcan be in any suitable form, such as, for example wire, fiber, looseparticulate, foam or sintered preforms. Likewise, although the feedstockof bulk-solidifying amorphous alloy is preferably in a pulverized formfor improved blending with the reinforcement material, any form suitablefor mixing may be utilized. The feedstock of bulk-solidifying amorphousalloy does not need to have an amorphous phase and it can be in itscrystalline form. However, the chemical homogeneity of the pulverizedparticles of bulk-solidifying amorphous alloy composition is preferable.The packing density (or packing efficiency) of the feedstock mixture ispreferably 30% and higher and most preferably 50% and higher.

The provided feedstock mixture may be blended and pressed under vacuumto aid the packing efficiency in the feedstock mixture. In one suchembodiment, the feedstock mixture is canned and sealed under vacuum in asoft and malleable metal, which is stable (i.e., having a meltingtemperature or sublimation point) at greater temperatures than themelting temperatures of the bulk-solidifying amorphous alloycomposition. Although any suitable pressure may be utilized, in oneembodiment of the invention, the vacuum pressure is better than 10⁻³Torr. Again although any suitable malleable metal may be utilized to canthe feedstock, in one exemplary embodiment the can material is astainless-steel or copper based metal.

In this process, during the densification step (2), the feedstock isheated such that the reinforcement material stays in solid form and thebulk-solidifying amorphous alloy composition is in the molten state. Asa result, the molten alloy is able to flow around the reinforcementmaterial and effectively lubricate the reinforcement material particles.Accordingly, when pressure is applied, the packing efficiency of thereinforcement material is improved such that a high packing density maybe obtained. Although any temperature, pressure, and time of thisprocess may be utilized, the superheat and the time of the densificationprocess is preferably selected to minimize any undesirable reactionsamong the reinforcement material particles.

In one exemplary embodiment the densification step is carried oututilizing extrusion process above the melting temperature of thebulk-solidifying amorphous alloy composition. However, the densificationstep may be carried out using any suitable technique, such as, forexample, by applying a hydro-static pressure above the meltingtemperature of the bulk-solidifying amorphous alloy composition, oralternatively by a hot-isostatic process (HIP) process above the meltingtemperature of the bulk-solidifying amorphous alloy composition.

In one, most preferred embodiment of the invention, during thedensification step (2), the feedstock mixture is fully-densified havinga packing efficiency greater than 99% and most preferably near about100%.

In one embodiment of the invention, as shown in the flow-chart in FIG.3, during the first cooling step (3), the densified mixture is cooledsufficiently fast to substantially retain the amorphous structure of thebulk solidifying amorphous alloy composition. In such an embodiment,subsequently, a re-heating step (4) is performed where the densifiedmixture is heated and formed/shaped (5) around or above the glasstransition of temperature of bulk-solidifying amorphous alloy such thatcrystallization of the amorphous material does not occur.

However, in the embodiment of the invention shown as a flow-chart inFIG. 4, the cooling rate of the first cooling step is not sufficient toform the amorphous phase in the bulk-solidifying amorphous alloy, inthis second embodiment, the second heating cycle is extended above themelting temperature of bulk-solidifying amorphous alloy. As such, theforming step (5) is carried out above the melting temperature. In thissecond embodiment, in the final quenching step (6), the formed objectmust be cooled sufficiently fast to form the amorphous structure of thebulk solidifying amorphous alloy composition such that an object isformed comprising a bulk-solidifying amorphous composite material.

In one specific embodiment of the invention shown as a flow-chart inFigure, the heating of the densified mixture in the forming/shaping step(5) may be extended to temperatures with an increased superheat of atleast 50° C. above the temperatures used in the densification step.

In another specific embodiment of the invention shown as a flow-chart inFigure, the re-heating cycle of the densified mixture in theforming/shaping step (5) is carried at substantially shorter time thanof the densification step.

In another specific embodiment of the invention shown as a flow-chart inFigure, the re-heating cycle of the densified mixture in theforming/shaping step (5) is carried at temperatures of at least 50° C.above the temperature of densification step; and at substantiallyshorter time than of the densification step.

In one embodiment of the invention, the aspect ratio of the fullydensified mixture is increased by a factor of at least twice in theforming/shaping step. In another embodiment of the invention, the aspectratio of the fully densified mixture is decreased by a factor of atleast twice in the forming/shaping step.

The invention is also directed to an article made by the material andprocess described above. Although any size and shaped article may bemade, in one embodiment of the invention, the article made of thecomposite material is a cylindrical rod with an aspect ratio of greaterthan 10 (defined as length divided by diameter) and comprises tungstenmetal as the reinforcement material at a volume fraction of greater than75%. In another preferred embodiment of the invention, the article ofcomposite material is a cylindrical rod with an aspect ratio of greaterthan 15 (defined as length divided by diameter) and comprises tungstenmetal as the reinforcement material at a volume fraction of greater than75%.

Again although any suitable dimensions may be utilized, in oneembodiment of the invention, the article of composite material is atleast 0.5 mm in all dimensions. In another embodiment of the invention,the article of the composite material is an article of “extreme” aspectratio, whereas one or two dimensions of the article is substantiallylarger (or smaller) than the other dimensions of the article. In onesuch embodiment of the invention, the article of the composite materialis a cylindrical rod with an aspect ratio of greater than 10 (where thelength is 10 times or more of the diameter). In such an embodiment, therob may and have a diameter of at least 10 mm. In another suchembodiment of the invention, the article of the composite material is adisc with an aspect ratio of less than 0.1 (where the diameter of thedisc is 0.1 times or less of the thickness).

Finally, although only tungsten metal reinforcement materials arediscussed above, in another embodiment of the invention, the article orat least a portion of the article of the composite material compriseslightweight-hard particles—such as SiC, SiN, BC, TiC, diamond—as thereinforcement material at a volume fraction of greater than 75%.Alternatively, the reinforcement material may compriselightweight-strong fibers—such as SiC, at a volume fraction of greaterthan 75%.

Although specific embodiments are disclosed herein, it is expected thatpersons skilled in the art can and will design alternativebulk-solidifying composites and methods to produce the bulk-solidifyingcomposites that are within the scope of the following description eitherliterally or under the Doctrine of Equivalents.

1. A method of forming a dense reinforcement-containing bulk solidifyingamorphous alloy-matrix composite material comprising: providing afeedstock of a bulk solidifying amorphous alloy having the capability ofretaining an amorphous state when cooled from above its meltingtemperature at a critical cooling rate of no more than about 500° C./s;dispersing and blending a plurality of pieces of a reinforcementmaterial with the bulk solidifying amorphous alloy feedstock undervacuum to form a blended mixture of reinforcement material and bulksolidifying amorphous alloy feedstock having a packing density of atleast 30% prior to densification; heating the mixture to a densificationtemperature above the melting temperature of the bulk solidifyingamorphous alloy and below the melting temperature of the reinforcementmaterial; densifying the mixture by applying a force to the mixture atthe densification temperature for a specified densification time;cooling the densified mixture below the glass transition temperature ofthe bulk solidifying amorphous alloy to form a solidified compositematerial; reheating the solidified composite mixture to a formingtemperature for a period of time less than the densification time,wherein said forming temperature is at least 50° C. higher than thedensification temperature; forming the reheated composite mixture into adesired shape at the forming temperature; and quenching the reheatedmixture to an ambient temperature to form an amorphous alloy-matrixcomposite material.
 2. The method as described in claim 1 wherein thecooling of the densified mixture is carried out at a cooling rate noless than the critical cooling rate such that the bulk solidifyingamorphous alloy matrix of the solidified composite material issubstantially amorphous, and wherein the forming temperature is betweenthe glass transition temperature of the bulk solidifying amorphous alloyand the crystallization temperature of the bulk solidifying amorphousalloy.
 3. The method as described in claim 1 wherein the cooling of thedensified mixture is carried out at a cooling rate less than thecritical cooling rate such that the bulk solidifying amorphous alloymatrix of the solidified composite material is substantiallycrystalline, and wherein the quenching of the reheated mixture iscarried out at a cooling rate no less than the critical cooling ratesuch that the amorphous alloy-matrix composite material is substantiallyamorphous.
 4. The method as described in claim 1 wherein the bulksolidifying amorphous alloy has a supercooled liquid regime of largerthan 60° C.
 5. The method as described in claim 1 wherein the bulksolidifying amorphous alloy has a supercooled liquid regime of largerthan 90° C.
 6. The method as described in claim 1 wherein the bulksolidifying amorphous alloy is described by the molecular equation:(Zr,Ti)_(a)(Ni,Cu,Fe)_(b)(Be,Al,Si,B)_(c), where a is in the range offrom 30 to 75, b is in the range of from 5 to 60, and c in the range offrom 0 to 50 in atomic percentages.
 7. The method as described in claim1 wherein the bulk solidifying amorphous alloy is described by themolecular equation: (Zr,Ti)_(a)(Ni,Cu)_(b)(Be)_(c), where a is in therange of from 40 to 75, b is in the range of from 5 to 50, and c in therange of from 5 to 50 in atomic percentages.
 8. The method as describedin claim 1 wherein the bulk solidifying amorphous alloy is described bythe molecular equation: (Zr)_(a)(Nb,Ti)_(b)(Ni,Cu)_(C)(Al)_(d), where ais in the range of from 45 to 65, b is in the range of from 0 to 10, cis in the range of from 20 to 40 and d in the range of from 7.5 to 15 inatomic percentages.
 9. The method as described in claim 1 wherein thebulk solidifying amorphous alloy contains a ductile crystalline phaseprecipitate.
 10. The method as described in claim 1 wherein thereinforcement material is stable at temperatures at least greater thanthe melting temperature of the bulk solidifying amorphous alloy.
 11. Themethod as described in claim 1 wherein the reinforcement materialcontains at least one refractory metal selected from the groupconsisting of tungsten, molybdenum, tantalum, niobium and their alloys.12. The method as described in claim 1 wherein the reinforcementmaterial contains at least one material selected from the groupconsisting of SiC, SiN, BC, TiC, WC, SiO2, diamond, graphite and carbonfiber.
 13. The method as described in claim 1 wherein the reinforcementmaterial takes a form selected from the group consisting of wire, fiber,loose particulate, foam and sintered preforms.
 14. The method asdescribed in claim 1 wherein the packing density of thepre-densification mixture is at least 50%.
 15. The method as describedin claim 1 wherein the step of applying a force occurs under vacuum. 16.The method as described in claim 1 wherein the step of applying a forceincludes extruding the mixture at a temperature above the meltingtemperature of the bulk-solidifying amorphous alloy.
 17. The method asdescribed in claim 1 wherein the step of applying a force includesapplying a hydro-static pressure to the mixture at a temperature abovethe melting temperature of the bulk-solidifying amorphous alloy.
 18. Themethod as described in claim 1 wherein the step of applying a forceincludes carrying out a hot-isostatic process on the mixture at atemperature above the melting temperature of the bulk-solidifyingamorphous alloy.
 19. The method as described in claim 1 wherein the stepof applying a force forms a densified mixture having a packing densityof greater than 99%.
 20. The method as described in claim 1 wherein thereinforcement material comprises a volume fraction of the solidifiedcomposite material of greater than 75%.